A Study in the Impeller-Volute Interactions of a Double-Suction Centrifugal Pump

2003 ◽  
Author(s):  
Kyung-Nam Chung ◽  
Pyun-Gu Park ◽  
Jin-Young Kim
Keyword(s):  
Velocity Field ◽  
Flow Field ◽  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Structured Grid ◽  
Pressure Fields ◽  
Block Structured

In this study, unsteady flow field of an industrial double-suction centrifugal pump has been solved to obtain the interaction between impeller and volute casing. Quasi-steady and unsteady methods have been used. A block-structured grid is employed to represent the complicated pump geometry. The velocity field and the pressure fields of the pump are analyzed for the rated point and off-design points. Magnitude of the interaction is evaluated numerically.

Numerical Study of Rotor–Stator Interaction of a Centrifugal Pump at Part Load With Special Emphasis on Unsteady Blade Load

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Nicolas Casimir ◽  
Xiangyuan Zhu ◽  
Markus Hundshagen ◽  
Gerhard Ludwig ◽  
Romuald Skoda
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Numerical Study ◽  
Measurement Data ◽  
Load Flow ◽  
Secondary Outcome ◽  
Pump Design ◽  
Part Load ◽  
Unsteady Characteristics

Abstract Three-dimensional (3D) unsteady Reynolds-averaged Navier–Stokes (URANS) flow simulations are conducted to investigate the highly unsteady flow field at part load operation of a centrifugal pump. By the availability of unsteady flow field measurement data in the impeller wake region, a thorough validation of the simulation method is performed. Grid independence of the results is ensured. Unsteady characteristics in terms of head and shaft power as well as transient blade loads are evaluated to assess the unsteady pump performance. Significant mis-loading of the blading is revealed when one blade passes the volute tongue and associated with the strong unsteady and 3D flow field in the impeller-volute tongue region. Negative radial velocity in the tongue region is the origin of a vortex at the blade pressure side and a subsequent pressure drop that leads to even temporally negative blade loading. The results provide a detailed insight in the complex part load flow field that might be utilized for an improved pump design. As a valuable secondary outcome, a comparison of results obtained by two widely used computational fluid dynamics (CFD) codes for pump flow simulation is provided, i.e., the commercial code ansyscfx and the branch foam-extend of the open source software openfoam. It is found that the results of both methods in terms of unsteady characteristics as well as local ensemble-averaged velocity field are consistent.

Periodically Unsteady Flow in a Single-Blade Centrifugal Pump: Numerical and Experimental Results

2005 ◽  
Author(s):  
F.-K. Benra ◽  
H. J. Dohmen ◽  
M. Sommer
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Sewage Water ◽  
Numerical Results ◽  
Experimental Results ◽  
Time Dependent ◽  
Pump Operation ◽  
Wide Range ◽  
Operating Points

The composition of sewage water with partially large portions of fibers and solids requires a special pump design, in order to avoid operational disturbances by clogging. In most applications for sewage water transport, single-stage pumps with single-blade impellers are used. With this special impeller geometry largest flow channels can be realized. So fibers and solids up to an appropriate size can be transported by the pump. This minimum impeller blade number however brings disadvantages for pump operation. The development of a pressure and a suction surface of the blade gives an asymmetric pressure distribution at the perimeter of the rotor outlet and a periodically unsteady flow field arises. In a numerical approach the time accurate flow in a single-blade centrifugal pump has been calculated by solving the 3-dimensional time dependent Reynolds averaged Navier-Stokes equations (URANS) in a wide range of pump operation. The investigation of the flow included all details between suction flange and pressure flange of the pump. The numerical results show a strong dependence from impeller position for all flow parameters. For the investigated operating points strong vortices have been obtained at particular impeller positions. Experimental results have been used to verify the numerical results of time dependent flow in the single-blade pump. The computed flow field has been compared to results which were obtained from optical measurements of flow velocities by Particle Image Velocimetry at different impeller positions. A very good qualitative agreement between measurements and calculations has been obtained for all investigated operating points.

scholarly journals Numerical Modelization of the Flow in Centrifugal Pump: Volute Influence in Velocity and Pressure Fields

2005 ◽  
Vol 2005 (3) ◽  
pp. 244-255 ◽  
Author(s):  
Miguel Asuaje ◽  
Farid Bakir ◽  
Smaïne Kouidri ◽  
Frank Kenyery ◽  
Robert Rey
Keyword(s):  
Centrifugal Pump ◽  
Cfd Simulation ◽  
Pressure Field ◽  
Flow Simulation ◽  
Turbulence Models ◽  
3D Flow ◽  
Structured Grid ◽  
Pressure Fields ◽  
Pump Shaft ◽  
Radial Thrust

A 3D-CFD simulation of the impeller and volute of a centrifugal pump has been performed using CFX codes. The pump has a specific speed of 32 (metric units) and an outside impeller diameter of 400 mm. First, a 3D flow simulation for the impeller with a structured grid is presented. A sensitivity analysis regarding grid quality and turbulence models were also performed. The final impeller model obtained was used for a 3D quasi-unsteady flow simulation of the impeller-volute stage. A procedure for designing the volute, the nonstructured grid generation in the volute, and the interface flow passage between the impeller and volute are discussed. This flow simulation was carried out for several impeller blades and volute tongue relative positions. As a result, velocity and pressure field were calculated for different flow rates, allowing to obtain the radial thrust on the pump shaft.

Simulation of Simplified Three-Dimensional Space Flow Velocity Field in Reservoir on the Condition of Unsteady Flow and its Application

2012 ◽  
Vol 203 ◽  
pp. 514-518
Author(s):  
Shi Ping Fan ◽  
Jian Ming Yang ◽  
Min Quan Feng ◽  
Bang Min Zheng
Keyword(s):  
Numerical Calculation ◽  
Velocity Field ◽  
Flow Field ◽  
Unsteady Flow ◽  
Flow Velocity ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Flow Velocity Field ◽  
Flood Period ◽  
Three Dimensional Space

In view of the complexity of the conventional simulation calculation method of three-dimensional flow field for the reservoir, and to analysis of the change of the reservoir’s flow field in flood period, in this paper, based on the unsteady flow numerical calculation, the simulation method for three-dimensional space flow velocity field of the reservoir in flood period was studied and applied to the Wenyuhe Reservoir. First refining the actual extraction of grid, and then having an unsteady flow numerical calculation for the reservoir, finally through layering and stripping the grid, three-dimensional space flow velocity field the reservoir on the condition of unsteady flow has been studied. The results showed that the reservoir velocity along the flow direction is becoming smaller, and surface velocity is fast; with the flow increase gradually, the unsteady flow has a great effect on the flow field of the reservoir’s concave bank. The grid can at will encryption, so the calculation precision can be effectively controlled and the process of simulation is easy to be programmed. The research results can simplify the complexity of the reservoir for three-dimensional numerical simulation, and up to providing theoretical support for reservoir flood control.

scholarly journals Steady and Unsteady Three-Dimensional Flow Field Downstream of an Embedded Stator in a Multistage Axial Flow Compressor: Part 1 — Unsteady Velocity Field

1998 ◽  
Author(s):  
J. Prato ◽  
B. Lakshminarayana ◽  
N. Suryavamshi
Keyword(s):  
Velocity Field ◽  
Flow Field ◽  
Unsteady Flow ◽  
Three Dimensional ◽  
Axial Flow ◽  
High Response ◽  
Axial Flow Compressor ◽  
Flow Features ◽  
Flow Compressor ◽  
Hot Film

A comprehensive investigation of the three-dimensional unsteady flow and thermal field downstream of an embedded stator in a multistage compressor, acquired with a high-response hot-film probe and aspirating probe, is presented and analyzed. Some of the earlier data (five-hole probe and high-response Kulite probe) from the same compressor is used with the present data to provide an integrated and comprehensive interpretation of the flow and thermal fields. The emphasis is on the unsteady flow, unsteady thermal, and integrated flow fields. Part 1 covers the description of the facility and the development of the hot-film technique for multistage flow field measurement. In addition, the unsteady velocity field is presented and interpreted. Part 2 provides an integrated assessment of the stagnation pressure, temperature and velocity fields to derive a comprehensive understanding of the time-averaged flow features. The final part covers velocity-velocity and velocity-temperature correlations and the assessment of their magnitudes in the average-passage equations. The results from an area traverse of the unsteady velocity field derived from a 45 degree slanted film probe downstream of the second stator of a three-stage axial flow compressor are presented and discussed in this paper. The measurements were conducted at the peak efficiency operating point using a four-rotation method. The ensemble-averaged unsteady three-dimensional velocity data is resolved into the time-averaged component, revolution and blade periodic, and aperiodic components. Some of the features of the rotor 2 flow, measured at the exit of stator 2, reveal the extent of the spread of the upstream rotor wakes and the unsteadiness due to rotor hub and leakage flow regions and levels of periodic and aperiodic unsteadiness. Both the revolution and blade periodic velocity fluctuations are seen to be significantly greater than the aperiodic fluctuations.

Methodology to Identify the Unsteady Flow Field Associated With the Loss of Acoustic Energy in the Vicinity of Circular Holes

2010 ◽  
Author(s):  
Jochen Rupp ◽  
Jon Carrotte ◽  
Adrian Spencer
Keyword(s):  
Velocity Field ◽  
Flow Field ◽  
Unsteady Flow ◽  
Acoustic Field ◽  
Acoustic Waves ◽  
Large Scale ◽  
Acoustic Power ◽  
Acoustic Energy ◽  
Absorption Mechanism ◽  
Linear Absorption

Thermo-acoustic instabilities in lean gas turbine combustors have been well reported over the past decade. One option by which the generation of potentially damaging, large scale, pressure amplitudes can be avoided is to increase the amount of damping within the combustion system using passive damping devices. Common to these devices is the absorption mechanism by which acoustic energy, associated with incident pressure fluctuations onto an orifice, generates an unsteady flow that cannot be converted back into acoustic energy. This paper is concerned with providing a greater understanding of this fundamental process. Experimental results are presented for a single orifice that is exposed to plane acoustic waves within a rectangular duct. Measurements of unsteady pressure enable the acoustic power absorbed by the orifice to be determined, whilst Particle Image Velocimetry (PIV) is used to measure the unsteady flow field. A method is outlined for identifying those features within the measured unsteady flow field that are responsible for absorption of the acoustic energy. This is based on a Proper Orthogonal Decomposition (POD) analysis of the velocity field and identification of the relevant modes. The method is validated for the non-linear and linear absorption regimes by comparing the energy of the relevant velocity field features with the energy absorbed from the acoustic field. The good agreement obtained indicates the success of the technique presented. The improved understanding of the mechanisms by which energy is transferred out of the acoustic field, and into the unsteady velocity field, explains many of the observed absorption characteristics. This improved understanding should lead to the design of optimized damping systems. The presented methodology is also thought to be the basis by which numerical, CFD based, predictions relating to the absorption of acoustic waves should be analyzed and validated.

scholarly journals Numerical Study of the Unsteady Flow Characteristics of a Jet Centrifugal Pump under Multiple Conditions

Processes ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 786
Author(s):  
Rong Guo ◽  
Rennian Li ◽  
Renhui Zhang ◽  
Wei Han
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Temporal Evolution ◽  
Guide Vane ◽  
Flow Characteristics ◽  
The Other ◽  
Flow Passage ◽  
Evolution Laws ◽  
Multiple Conditions

To study the reasons for the low efficiency of jet centrifugal pumps (JCPs) and the mechanism of unsteady flow characteristics under multiple conditions, taking a JET750G1 JCP as the object, three-dimensional steady and unsteady numerical calculations of the model pump were carried out using the k–ω turbulence model. The transient fluctuation characteristics of the flow field in the major flow passage components and the spatial and temporal evolution laws of vortices in the rotor–stator cascades were analyzed. The accuracy of the numerical method was verified by experiments. The results show that there are various scales of flow distortion phenomena in the chamber of the JCP, such as eddies, blockage of the flow passage, recirculation, secondary flow, and circulation, which not only cause great hydraulic loss, but also destroy the flow stability, symmetry, and balance in the other flow passage components. This is an important reason for the obviously lower efficiency of a JCP compared to a general centrifugal pump. The spatial and temporal evolution laws of vortices in the rotor–stator cascades are mainly related to the relative positions of the impeller blades and guide vane blades. The formation mechanism of the unsteady flow field fluctuation characteristics of JCPs is mainly related to the number of blades in the rotor–stator cascades and the operation parameters of the pump. The fluctuation intensity of the flow field inside the impeller and guide vane is obviously greater than that in the other flow areas, reflecting that the rotor–stator interaction is the decisive factor affecting the unsteady flow characteristics of a JCP under multiple conditions.

scholarly journals Study on Flow Characteristics in Volute of Centrifugal Pump Based on Dynamic Mode Decomposition

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Yi-bin Li ◽  
Chang-hong He ◽  
Jian-zhong Li
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
Rate Condition ◽  
Blade Passing Frequency ◽  
Mode Decomposition

To investigate the unsteady flow characteristics and their influence mechanism in the volute of centrifugal pump, the Reynolds time-averaged N-S equation, RNG k-ε turbulence model, and structured grid technique are used to numerically analyze the transient flow-field characteristics inside the centrifugal pump volute. Based on the quantified parameters of flow field in the volute of centrifugal pump, the velocity mode contours and oscillation characteristics of the mid-span section of the volute of centrifugal pump are obtained by dynamic mode decomposition (DMD) for the nominal and low flow-rate condition. The research shows that the first-order average flow mode extracted by DMD is the dominant flow structure in the flow field of the volute. The second-order and third-order modes are the most important oscillation modes causing unsteady flow in the volute, and the characteristic frequency of the two modes is consistent with the blade passing frequency and the 2x blade passing frequency obtained by the fast Fourier transform (FFT). By reconstructing the internal flow field of the volute with the blade passing frequency for the nominal flow-rate condition, the periodic variation of the unsteady flow structure in the volute under this frequency is visually reproduced, which provides some ideas for the study of the unsteady structure in the internal flow field of centrifugal pumps.

scholarly journals Measurements of the Unsteady Flow Field Within the Stator Row of a Transonic Axial-Flow Fan: I — Measurement and Analysis Technique

1987 ◽  
Author(s):  
K. L. Suder ◽  
T. H. Okiishi ◽  
M. D. Hathaway ◽  
A. J. Strazisar ◽  
J. J. Adamczyk
Keyword(s):  
Velocity Field ◽  
Flow Field ◽  
Unsteady Flow ◽  
Stokes Equations ◽  
Axial Flow ◽  
Navier Stokes ◽  
Axial Flow Fan ◽  
Rotor Wake ◽  
Navier Stokes Equations ◽  
Measurement And Analysis

This two-part paper presents detailed laser anemometer measurements of the unsteady velocity field within the stator row of a transonic axial-flow fan. The objective of this study was to provide additional insight into unsteady blade-row interactions within high speed compressors which affect stage efficiency, energy transfer, and other design considerations. Part I of this paper describes the measurement and analysis techniques used for resolving the unsteady flow field features. The ensemble-average and variance of the measured velocities are used to identify the “rotor-wake-generated” and “unresolved” unsteadiness, respectively. The term “rotor-wake-generated” unsteadiness refers to the unsteadiness generated by the rotor wake velocity deficit and the term “unresolved” unsteadiness refers to all remaining contributions to unsteadiness such as vortex shedding, turbulence, mass flow fluctuations, etc. A procedure for calculating auto and cross correlations of the rotor-wake-generated and unresolved unsteady velocity fluctuations is described. These unsteady-velocity correlations have significance since they also result from a decomposition of the Navier-Stokes equations. This decomposition of the Navier-Stokes equations resulting in the velocity correlations used to describe the unsteady velocity field will also be outlined in this paper.

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